Cloud computing systems, generally, are distributed processing systems including multiple computing devices connected by and communicating over a network. Software applications may be run “in the cloud” by configuring them to execute across one or more of the computing devices in a particular cloud computing system. The computing devices of a cloud computing system may each execute separate copies of the software application, or, in some cases, the operations of the software application may be split among different computing devices and executed in parallel. A cloud computing system may include a plurality of cloud computing instances representing resources available for executing applications. Each instance may be a physical computing device having particular capabilities (storage size, processing speed, network bandwidth, etc.), or may be a virtual computing device having particular capabilities. A particular cloud computing system may offer different instance types having different sets of capabilities for executing software applications.